json parsing

{"success":"0000","status":"100","result":{"code":"00","msg":"22"}} 형태의 json에서 code와 msg를 분리하고 싶다.

//example.
 String jsonString = "{"success":"0000","status":"100","result":{"code":"00","msg":"22"}}
";
JSONObject jObject = new JSONObject(jsonString);
String resultObj = jObject.getString("result");

String code = jObject.getJSONObject("result").getString("code");
=> 00 출력

import lombok.*;

@Getter
@Setter
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class TestDto {
    private String success;
    private String status;
    private resultGroup result;
    @Override
    public String toString() {
        return success;
    }
}

@RestController
public class TestController {
    @GetMapping("/test111")
    public String  getExceptionTest123 () throws JSONException {
        TestDto testObj= new TestDto().builder()
                .success("0000")
                .status("100")
                .result(resultGroup.builder().code("00").msg("22").build())
                .build();
        System.out.println(testObj);

        GsonBuilder builder = new GsonBuilder();
        builder.serializeNulls();
        Gson gson = builder.create();
        String jsonString = gson.toJson(testObj);
        System.out.println(jsonString);

        JSONObject jObject = new JSONObject(jsonString);
        String resultObj = jObject.getString("result");

        String code = jObject.getJSONObject("result").getString("code");
        System.out.println(code);

        return resultObj;
    }